Apoptosis induced by preservation and reperfusion in canine lung transplantation

STUDY ON THE PROTECTION OF ISOLATED RABBIT'S PULMONARY ISCHEMIA REPERFUSION INJURY BY ADDING TANSHINONE IIA INTO LOW POTASSIUM DEXTRAN SOLUTION

Purpose: This study investigates the protective effect of Tanshinone IIA (Tan IIA) on isolated rabbit's pulmonary ischemia reperfusion injury (IRI) and discusses its potential for the treatment of microcirculation disorders. Methods: We chose isolated rabbit's IRI as our experimental models, and randomly divided 24 New Zealand rabbits into two groups. For the control group (L), the lungs were perfused with Low Potassium Dextran (LPD) solution under 4[Formula: see text]C, and then it was preserved under 10[Formula: see text]C. For the experimental group (LT), the lungs were perfused and preserved with LPD[Formula: see text]Tan solution using the same approach. After the lungs have been preserved for 18[Formula: see text]h, we again perfused it for another 30 min. After reperfusion was completed, we determined the contents of SOD, NO, and MDA immediately. The wet to dry weight ratio (W/[Formula: see text] was then obtained. Finally, we use a combination of light microscopy and transmission electron microscopy to observe the ultra-structural changes of lung tissues. Results: We discovered that the contents of SOD and NO in group LT were higher than that in group L ([Formula: see text]). However, the MDA and the W/D values in group LT were lower than that in group L ([Formula: see text] or [Formula: see text]). We also observed that part of the tissues has hyperemia, edema, and congestion. Under the light microscopy, the structures of the pulmonary alveoli, bronchi, and capillaries were complete. But under high-power field, group L had a more obvious phenomenon of alveolar epithelium and capillary epithelium cells swelling and hypertrophy with respect to group LT. It could be observed that in the partial tissues, erythrocytes exuded from alveoli and the interval tends to widen in the alveoli. Under transmission electron microscopy, group L is observed to have mitochondria swelling, vacuolization, and even autosome edge accumulation. Microvillus of cell Type II significantly decreased or disappeared. Blood–air barrier swelled severely and a portion of it was cracked. The phenomena above were obviously reduced for group LT. Conclusion: Our experiments confirmed that adding Tan IIA into LPD solution can reduce the isolated rabbit's IRI effectively.

Protective effect of tetramethylpyrazine on myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a common pathological and physiological phenomenon. Tetramethylpyrazine is the extract of the traditional Chinese medicine Chuanxiong, which can exert protective effects on MIRI in multiple ways. This paper reviewed the current research progress and evidence about the cardiovascular effects of tetramethylpyrazine, which included protecting mitochondria and improving energy metabolism, scavenging oxygen free radicals (OFRs) to inhibit lipid peroxidation, attenuating calcium (Ca(2+)) overload and maintaining Ca(2+) homeostasis in cells, inhibiting apoptosis and protecting myocardial cells, interfering with the inflammatory reaction and mitigating cell injury, interfering with cell signaling pathways, and improving function of endothelial cells and protecting myocardial cells. However, further rigorously designed randomized controlled trials are warranted.

Effect of pyruvate and HEPES on rat lung allograft acidosis and cell death after long-term hypothermic storage

BACKGROUND

We have previously demonstrated that adding pyruvate to Perfadex increased graft metabolism during 24-hour storage and improved reperfusion lung function. This increased metabolism was associated with progressively lower pH of the storage solution during the preservation interval.

OBJECTIVE

To determine whether more effective pH regulation would result in further improvements in lung survival after hypothermic storage.

MATERIALS AND METHODS

Rat lungs were stored for 24 hours in Perfadex, Perfadex with HEPES (N-2-hydroxyethylpiperazine-propanesulfonic acid) buffer, pyruvate-modified Perfadex, and pyruvate-modified Perfadex with HEPES. Change in pH in the storage solution was measured. Structural lung injury was evaluated using hematoxylin-eosin stained tissue sections. Cell death was quantified by measuring necrotic cells using trypan blue exclusion and apoptotic cells via the TUNEL (terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick-end labeling) assay.

RESULTS

Lungs stored in Perfadex demonstrated the greatest degree of cell death. Lungs in the Pyruvate group exhibited decreased cell death despite greater acidosis. The addition of HEPES reduced cell death and preservation solution acidosis in both Perfadex and pyruvate-modified Perfadex (P < .05). Almost all cell death resulted from necrosis. Adding pyruvate to the preservation solution increases acid formation during storage, but decreases cell death. HEPES ameliorates this acidosis and decreases allograft cell destruction.

CONCLUSION

Increasing the preservation solution buffering capacity may be a simple strategy for improving lung preservation for transplantation.

Pretreatment with calcitonin gene-related peptide attenuates hepatic ischemia/reperfusion injury in rats

OBJECTIVE

Oxygen free radicals and apoptosis play important roles in liver ischemia/reperfusion (I/R) injury. We sought to investigate the protective effect of calcitonin gene-related peptide (CGRP) to attenuate liver I/R injury due to oxygen free radicals and apoptosis.

MATERIALS AND METHODS

Harvested rat livers were perfused via the portal vein with 60 mL of 4 degrees C histidine-tryptophan-ketoglutarate (HTK) solution alone in the control group, or with the same solution containing CGRP (3 microg/10 g body weight) in the experimental group. After 24 hours of cold storage, hepatic enzyme leakage, portal venous pressure, oxygen consumption, total adenine nucleotides (TAN), bile production, lipoperoxide (LPO) release, apoptosis, and histochemical changes were evaluated upon 45 minutes of isolated reperfusion.

RESULTS

Compared with control livers, CGRP-treated organs showed significantly decreased alanine aminotransferase (ALT) and glutamate-lactate dehydrogenase (GLDH) leakage and portal venous pressure (2.0 +/- 0.3 vs 4.0 +/- 0.4 mmHg; P < .01), with significantly increased bile production (8.56 +/- 0.76 vs 3.34 +/- 0.68 microL/g/45 min; P < .01), oxygen consumption (5.14 +/- 0.4 vs 2.57 +/- 0.2 microL/g/min; P < .01), and total adenine nucleotides (TAN) (11.1 +/- 0.71 vs 7.02 +/- 0.53 micromol/g; P < .01) upon reperfusion as signs of recovered viability. We observed infrequent positive terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling (TUNEL) staining, especially in sinusoidal lining cells (SLC). The percentage of TUNEL-positive cells in the CGRP group was significantly decreased compared with the control group: (4.1 +/- 0.67 vs 8.0 +/- 1.27; P < .05). Perfusate levels of low molecular weight (LMW) histone-associated DNA fragments (0.36 +/- 0.04 vs 0.53 +/- 0.06 AU; P < .05) were also decreased, coupled with strong 5'-nucleotidase (5'-NT) and LDH activity staining concentrated on the endothelial cells. LPO release in the perfusate was largely decreased: (0.12 +/- 0.02 vs 0.36 +/- 0.04 nmoL/g, P < .01).

CONCLUSION

CGRP ameliorated liver I/R injury due to reactive oxygen species and apoptosis.

Overexpression of Human Bcl-2 in Syngeneic Rat Donor Lungs Preserves Posttransplant Function and Reduces Intragraft Caspase Activity and Interleukin-1?? Production

BACKGROUND

A significant cause of primary graft failure in lung transplantation is ischemia-reperfusion (I/R). I/R injury generates proinflammatory cytokines, such as interleukin (IL)-1beta, and activates the caspase-mediated pathways of alveolar epithelial apoptosis. The authors investigated whether gene transfer of the human antiapoptotic protein Bcl-2 by means of intratracheal adenoviral administration would preserve posttransplant lung function and reduce intragraft activated caspase activity and IL-1beta production in syngeneic rat donor lung grafts.

METHODS

First, 1.0 x 10(9) plaque-forming units of AdvBcl-2 in phosphate-buffered saline (PBS), AdvNull empty vector in PBS, or PBS alone was administered intratracheally to ACI (RT1(a)) rats. Then, the left lungs were procured after 24 hr of in vivo incubation and orthotopically transplanted after 1 hr of cold ischemia into syngeneic recipients. After 2 hr of reperfusion, peak inspiratory pressures (PIP) and donor pulmonary vein PaO(2) was measured in all grafts; grafts were then excised and protein extracts were analyzed by enzyme-linked immunosorbent assay (ELISA) and activated caspase-3 and caspase-9 assays.

RESULTS

Human Bcl-2 transgene overexpression in donor lung grafts was demonstrated by ELISA of tissue homogenates. Pretreatment of donor lungs with AdvBcl-2 resulted in reduced PIP and increased lung isograft pulmonary vein PaO(2) compared with AdvNull or PBS-alone treated controls. In addition, AdvBcl-2 pretreatment led to diminished cytochrome c release into cytosolic extracts and reduced intragraft IL-1beta production and inhibited intragraft caspase-3 and caspase-9 activity.

CONCLUSIONS

Adenoviral overexpression of human Bcl-2 protein limits I/R injury in rat lung isografts. These data suggest that the use of Bcl-2 gene transfer to human lung donors may reduce the oxidative stress of pulmonary grafts after transplantation in clinical lung transplantation.

Ultrastructural evaluation of the protective effect of nitroglycerin in preservation-reperfusion injury of rat lungs

AIM OF STUDY

Nitric oxide (NO) has been reported as a favorable protective supplement in donor lung preservation, but related ultrastructural studies are rare in the literature. This study was performed to assess the ultrastructural changes and to evaluate the protective effect of NO as donor nitroglycerin (NTG) treatment of ischemia-reperfusion injury in rat lungs.

MATERIALS AND METHODS

Fifteen Sprague-Dawley rats weighing 300 to 350 g were used in this study. The NTG group (n = 5) used intravenous administration followed by mixture in the University of Wisconsin (UW) solution. For the non-NTG group (n = 5), we injected the same amount of normal saline intravenously followed by admixture in the UW solution. The heart-lung blocks were removed, weighed, and kept in UW solution for 24 hours at 10 degrees C. Reperfusion using human blood diluted in Krebs-Hensleit solution was done for 60 minutes. For the control group (n = 5), we injected the same amount of normal saline intravenously, and removed the lungs with no preservation and reperfusion procedures.

RESULTS

The non-NTG group showed multiple patchy areas of alveolar collapse with marked swelling and destruction of type I epithelial cells, loss of type II cell surfactant granules, endothelial swelling and papillary projection, interstitial edema, and alveolar macrophages with active phagocytosis of the destroyed materials. The NTG group showed similar ultrastructural changes, but in a lesser severity compared with the non-NTG group.

CONCLUSION

Administration of the NTG reduced the ischemia-reperfusion injury in the rat donor lungs. Ultrastructural examination was an effective tool to evaluate the protective effect of NTG in ischemia-reperfusion procedures of donor lungs.